std::tuple_size(std::array)
From cppreference.com
Defined in header <array>
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template< class T, std::size_t N > struct tuple_size< std::array<T, N> > : |
(since C++11) | |
Provides access to the number of elements in an std::array as a compile-time constant expression.
Inherited from std::integral_constant
Member constants
value [static] |
N , the number of elements in the array (public static member constant) |
Member functions
operator std::size_t |
converts the object to std::size_t, returns value (public member function) |
operator() (C++14) |
returns value (public member function) |
Member types
Type | Definition |
value_type
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std::size_t
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type
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std::integral_constant<std::size_t, value> |
Example
Run this code
#include <iostream> #include <array> template<class T> void test(T) { int a[std::tuple_size<T>::value]; // can be used at compile time std::cout << std::size(a) << '\n'; } int main() { std::array<float, 3> arr; test(arr); }
Output:
3
See also
Structured binding (C++17) | binds the specified names to sub-objects or tuple elements of the initializer |
(C++11) |
obtains the size of tuple at compile time (class template specialization) |